Opus 5.5 dramatically cuts em-dash usage, blurring AI writing detection

jonathan_wilke · x · 2026-09-29

arvidkahl notes that em-dash frequency in Claude Opus 5.5's email prose has dropped significantly — the once-telltale AI writing marker is fading. He argues detecting AI writing will eventually become impossible, calling it both a good and a bad thing. jonathanwilke quips that Opus 5.5 has 'cracked the secret code of copywriting.'

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